Center pivot irrigation system position sensing system

ABSTRACT

A system and method for determining a position of a center pivot irrigation system includes positioning a tower unit on the rotatable arm of the irrigation system, determining a distance between the arm&#39;s rotation center and the tower unit, calculating coordinates of the tower unit along a path of the tower unit as the arm rotates, and associating an action of the irrigation system with coordinates of the tower unit location that correspond to the position of the arm where the action is to occur. Optionally, the action of the irrigation system and the coordinates of the location of the tower unit are downloaded to a remote unit located adjacent to the irrigation system. Optionally, current location coordinates of the tower unit are determined using a GPS receiver at the tower unit. Optionally, the current location coordinates are transmitted from the tower unit to the remote unit. Optionally, the current location coordinates are compared to the coordinates of the location of the action. If a substantial match of the current location coordinates with the location coordinates associated with an action is detected, the action may be initiated by the remote unit through controls of the irrigation system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to apparatus for sensing the position of acenter pivot irrigation system in a field, and more particularlypertains to a new system for determining the position of the rotatablearm of a center pivot irrigation system using data from a GlobalPositioning Satellite (GPS), which may be used in controlling variousaspects of the function of the center pivot irrigation system using anetwork-based system interface.

2. Description of the Prior Art

Irrigation systems have been employed for years to distribute water toareas of land on which a crop is growing. One type of irrigation system,the so-called “center pivot” system, employs a central tower about whicha rotatable arm pivots, or rotates, at an elevated position above theground. A conduit extends along this rotatable arm and radiatesoutwardly from the center tower, and water is sprayed or otherwisedistributed from the conduit at points along the conduit. The rotatablearm includes one or more towers to maintain the conduit in the elevatedposition above the ground, and each of the towers is typically supportedby one or more wheels that rotate while the rotatable arm is pivotedabout the center tower. The radially-outermost tower is typically calledthe end tower, and the end tower may include an “end gun” that sprayswater radially outward from the end tower of the rotatable arm.

A number of operational aspects of the center pivot may be controlled,including the starting and the stopping points for the rotatable arm aswell as the “on” and “off” points for the end gun, which may be turnedoff while the rest of the center pivot system continues to distributewater (such as when the end gun would spray water on a road adjoiningthe field). Conventionally these aspects are controlled in the field bya controller that is positioned in the field and programmed in thefield. The operation of the various aspects of the center pivotirrigation system is then keyed upon the angular position of therotatable arm, which is often determined by a sensor at the center towerthat detects the movement or the angular position of the rotatable armrelative to a reference angular position, such as a northward extendingposition. Thus, as the rotatable arm pivots and the angular position ofthe rotatable arm changes, various operational aspects of the centerpivot irrigation system may be initiated, adjusted, or terminated.

Recently, there have been attempts to use Global Positioning System(GPS) technology to determine the orientation of the rotatable arm,using one, two, three or more GPS antenna/receiver units. However, thesystems tend to be relatively complex, particularly since the knownGPS-based systems still rely upon the technique of determining theangular orientation of the rotatable arm for controlling the centerpivot irrigation system. For example, the system described in U.S. Pat.No. 6,928,339 to Barker requires the user to determine the coordinatesof the location of the center pivot in the field, program thecoordinates of the center pivot location into the control system in thefield, and then the system continuously calculates and recalculates theazimuth or angular orientation of the rotatable arm using thecoordinates of the center pivot location and the coordinates supplied bya GPS receiver unit mounted on one of the towers, and then compares thecurrent azimuth with the azimuths associated with various actions forthe irrigation system in an operational program stored on the irrigationsystem. This approach is believed to be unnecessarily complex for thispurpose, and does not readily lend itself to remotely monitoring of theangular orientation of the rotatable arm, or to remotely controlling theoperation of the various aspects of the center pivot irrigation system.

Further, most if not all known systems utilize monitoring andprogramming operations that are performed in the field, or at least mustbe changed in the field, and this factor makes the operation of thesystem more difficult, or at least inconvenient, for the operator of thesystem, especially for operators that are responsible for monitoring andcontrolling multiple center pivot irrigation systems.

It is therefore believed that there is a need for a position sensing andcontrolling system for center pivot irrigation system that facilitatesremote monitoring and controlling of a center pivot irrigation systemthat is not unnecessarily complex in design.

SUMMARY OF THE INVENTION

The present invention provides a new irrigation arm position sensingsystem wherein the same can be utilized for determining the position ofthe rotatable arm of a center pivot irrigation system using data from aGPS receiver, and may be used for controlling the center pivotirrigation system using a network-based system interface.

In general, the invention employs a system of determining a location ofan element located on the rotatable arm of the center pivot irrigationsystem to determine a position of the rotatable arm relative to thecenter pivot.

To attain this, the present invention generally comprises a method fordetermining a position of a rotatable arm of a center pivot irrigationsystem. The method may comprise positioning a tower unit on therotatable arm of the irrigation system, determining a distance between acenter of rotation of the rotatable arm and the tower unit, calculatingcoordinates of the tower unit along a path of the tower unit as therotatable arm pivots about the center of rotation, and associating anaction of the irrigation system with coordinates of the location of thetower unit that correspond to the position of the rotating arm where theaction of the irrigation system is to occur.

Optionally, the action of the irrigation system and the coordinates ofthe location of the tower unit may be downloaded to a remote unitlocated adjacent to the center pivot irrigation system. Also, currentlocation coordinates of the tower unit may be determined using a GlobalPositioning Satellite (GPS) receiver at the tower unit. Further, thecurrent location coordinates of the tower unit may be transmitted fromthe tower unit to the remote unit. The current location coordinates ofthe tower unit may be compared to the coordinates of the location of atleast one action of the irrigation system, and the step of comparing mayoccur at the remote unit. If a substantial match of the current locationcoordinates with one of the action coordinates associated with an actionis detected, then the action corresponding to the current locationcoordinates may be initiated by the remote unit through controls of thecenter pivot irrigation system.

In another aspect of the invention, a system for determining a positionof a rotatable arm of a center pivot irrigation system is disclosed. Thesystem may comprise a tower unit for positioning on the rotatable arm ata distance from the center pivot of the irrigation system, the towerunit being positionable at an end tower of the irrigation system. Thetower unit may comprise a Global Positioning Satellite (GPS) receiverconfigured to determine location coordinates of the tower unit, and afirst transmitter for communicating the location coordinates. The systemmay also include a remote unit for positioning proximate to the towerunit for receiving location coordinates from the tower unit. The remoteunit may comprise a first receiver for receiving the locationcoordinates transmitted by the first transmitter of the tower unit, asecond transmitter for transmitting the location coordinates of thetower unit to a communication network, and a comparator configured tocompare the location coordinates of the tower unit to at least onelocation coordinates corresponding to at least one action of theirrigation system.

There has thus been outlined, rather broadly, the more importantfeatures of the invention in order that the detailed description thereofthat follows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are additionalfeatures of the invention that will be described hereinafter and whichwill form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of otherembodiments and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting.

As such, those skilled in the art will appreciate that the conception,upon which this disclosure is based, may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

A significant advantage of the present invention is the simplicity ofassociating actions or functions of the irrigation system with thecoordinates of the location of a tower unit positioned on theirrigations system's rotatable arm when the action or functions is tooccur, so that the system is able to compare the coordinates associatedwith the action or function with the coordinates of the currentlocation, and when a substantial match occurs, the action or function isinitiated. The present invention does not require the calculation ofangle or azimuths using multiple coordinates to determine the currentposition of the rotatable arm.

Further advantages of the invention, along with the various features ofnovelty which characterize the invention, are pointed out withparticularity in the claims annexed to and forming a part of thisdisclosure. For a better understanding of the invention, its operatingadvantages and the specific objects attained by its uses, referenceshould be made to the accompanying drawings and descriptive matter inwhich there are illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and objects of the inventionwill become apparent when consideration is given to the followingdetailed description thereof. Such description makes reference to theannexed drawings wherein:

FIG. 1 is a schematic diagrammatic depiction of one version of a newirrigation arm position sensing apparatus according to the presentinvention, which provides both location monitoring and operationcontrolling aspects.

FIG. 2 is a schematic diagrammatic depiction of another version of thepresent invention, which primarily provides location monitoring aspects.

FIG. 3 is a schematic perspective view of an illustrative center pivotirrigation system with the location sensing system of the presentinvention.

FIG. 4 is a schematic flow chart diagram of one aspect of the method ofthe present invention.

FIG. 5 is a schematic flow chart diagram of another aspect of the methodof the present invention.

FIG. 6 is a schematic flow chart diagram of another aspect of the methodof the present invention.

FIG. 7 is a schematic depiction of the map/image and sweep of thepresent invention.

FIG. 8 is a schematic depiction of the map/image of the presentinvention showing the band of operation of the end gun.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference now to the drawings, and in particular to FIGS. 1 through8 thereof, a new irrigation arm position sensing system embodying theprinciples and concepts of the present invention and generallydesignated by the reference numeral 10 will be described.

In general, the irrigation arm position sensing system 10 of theinvention employs a technique of determining a present location of anelement of the system 10 that is mounted on the center pivot irrigationsystem 1, and comparing the present location of the element to a numberof locations stored on the system 10, and then executes a function oraction of the irrigation system 1 that is associated with that locationduring the operation of the irrigation system. The need to calculate theangular orientation of the center pivot irrigation system 1 is thusrendered superfluous and unnecessary for control of the irrigationsystem 1.

In greater detail, as best illustrated in FIGS. 1 and 2 of the drawings,one aspect of the invention is the system 10 that performs theoperational aspects of the invention that are further described later inthis specification. The system 10 may be embodied in at least two forms,which are depicted in FIGS. 1 and 2, although those skilled in the artwill recognize that many other forms may be employed to perform theinventive operation.

Initially, for the purposes of this description, it will be useful toidentify some of the pertinent elements of a center pivot irrigationsystem 1, such as the partial view of an irrigation system shown in FIG.3 of the drawings. The center pivot irrigation system 1 includes acenter pivot or tower 2 through which water flows to a rotatable arm 3,which includes a conduit or pipe 4 that radiates outwardly from thecenter pivot 2, and is supported by one or more towers 5 that are inturn supported on typically two or more wheels 6 that traverse thesurface of the field that is to be watered. Various support trusses andthe like may be employed to support the pipe 4 between the towers 5. Theendmost tower 7 of the rotatable arm 3 may be provided with an end gun 8that directs water outwardly from the end tower to reach areas of thefield that are not traversed by the rotatable arm 3. The center pivotirrigation system 1 may have a number of functions that may becontrolled. Conventionally, a control box or panel 9 is located in thefield of the center pivot irrigation system 1, often at the center pivot2, which can control the operation of the various elements and functionsof the irrigation system through a program set at the control panel 9.

FIG. 1 of the drawings depicts one embodiment of the position sensingsystem 10 of the invention that is highly suitable for monitoring thelocation of the rotatable arm 3 of the center pivot irrigation system 1as well as controlling various operations or functions of the irrigationsystem 1. In this embodiment, the position sensing system 10 may includea tower unit 12 that may be positioned on one of the towers 5 (or otherportion) of the center pivot irrigation system 1, as long as the unit 12is sufficiently spaced or separated from the center pivot to create acircular path that exceeds the expected accuracy of the GPS receiver.The tower unit 12 is preferably, but not necessarily, positioned on theendmost tower 7 of the system 1. A remote unit 14 may also be includedin the system 10, and while its position or location with respect to thecenter pivot irrigation system 1 is less important than the position ofthe tower unit 12, the remote unit 14 should be within communicationdistance (either wireless or wired) from the remote unit 12. In someembodiments of the invention, the remote unit is located with thecontrol panel 9, which (as previously noted) is often located at thecenter pivot 2, so that the remote unit can pass control commands to thecontrolling circuitry in the control panel.

The tower unit 12 of the system 10 may include a number of elements,including a GPS receiver 16 for receiving GPS satellite signals (as wellas other positioning signals) that indicate the coordinates of thelocation of the tower unit 12, as well as the tower 5 or other portionof the center pivot irrigation system that the tower unit is mounted on.The tower unit 12 may also include a means of communicating with theremote unit 14, and this communication means preferably may be awireless communication device 18. The wireless communication device 18may communicate, for example, over radio frequencies, but those skilledin the art will recognize that other wireless (and wired) communicationtechnologies may be employed without departing from the invention.

The remote unit 14 of the system 10 may also include a number ofelements, such as an additional means suitable for communication withthe wireless communication device 18. In one embodiment of theinvention, the means for communication of the remote unit 14 comprises asecond wireless communication device 20 that communicates in a mannercompatible with the first wireless communication device 18. As notedpreviously, the communication devices 18, 20 could be wiredcommunication devices, although the wireless capability has severaladvantages, including the ability to move the tower unit 12 (and theremote unit 14, for that matter) between towers and even between centerpivot irrigation systems without having to route and reroute wires. Withthe provision of the communication device 20 in the remote unit 16, thetower unit 12 is able to communicate location information to the remoteunit 14, and this location information can be, for example, communicatedto the control panel 9 for triggering operations or functions of thecenter pivot irrigation system 1. Optionally, the communication devices18, 20 may each be capable of both transmitting and receiving (e.g., atransceiver) so that, for example, the remote unit may query the towerunit as to status, and even transmit commands to be executed at thetower, such as turning an end gun “on” and “off”.

The remote unit 14 may further include another means for communicatingthat is suitable for communicating over longer distances for the purposeof communicating with entities at a greater distance. For example, theentity may accessible through the Plain Old Telephone System (POTS) orwireless communication network and the entity may reside on a datanetwork. In one of the preferred implementations of the invention, thecellular telephone system is utilized and a cellular transceiver 22 isemployed in the remote unit 14 to provide communication ability to acellular antenna or tower in the region of the center pivot irrigationsystem. The entity may thus be a web server 26 that is able tocommunicate with the POTS or cellular telephone network 24 and also withthe Internet data network. Of course, other means for communicating maybe employed, but as access points to cellular networks (i.e., antennas)become more ubiquitous, even in rural areas, the cellular transceiver 22provides wireless communication to the cellular network 24 (and thusprovides access to the POTS network) without having to run a hard wiredconnection to the field, which can be prohibitively expensive. It willbe recognized by those skilled in the art that the type or types ofnetworks on which the invention is implemented may be varied withoutdeparting from the spirit of the invention. The cellular transceiver 22of the remote unit is thus able to communicate with the web server 26through the cellular network 24 by dialing the web server. The webserver 26 is thereby able to receive location and status informationfrom the remote 14 and tower 12 units, while the server is able toprovide operational programs to the remote unit 14 and the control panel9. The web server 26 is in turn accessible by the user's or customer'scomputer 28 through the Internet or other network. The user is thus ableto communicate instructions, or programs of instructions, to the remoteunit and the control panel of the center pivot irrigation system.

FIG. 2 of the drawings depicts another embodiment of the positionsensing system 10 of the invention that is highly suitable formonitoring the location of the rotatable arm 3 of the center pivotirrigation system 1. As in the embodiment of FIG. 1, the tower unit 12is positioned on one of the towers 5, and may be on the endmost tower 7.In this implementation, the tower unit 12 includes the GPS receiver 16for receiving GPS satellite signals and determining the location of thereceiver (and thus the tower unit 12). The tower unit also includes thecellular transceiver 22 for transmitting the location information to thecellular or other communication network 24, and through the cellularnetwork to the web server 26. Similarly, this provides access throughthe Internet to the customer's computer 28. In this embodiment, theremote unit 14 is not present, and the ability of the system 10 tocontrol the functions or actions of the center pivot irrigation system 1is limited or completely absent.

One aspect of the invention involves a method of determining a locationof the rotatable arm of a center pivot irrigation system using signalsfrom a GPS satellite, and using that location information to controlaspects of the operation of the center pivot irrigation system. In someembodiments of the invention, control instructions are transmitted tothe center pivot irrigation system over a network (such as the POTScommunication network) and the location information is used in applyingthose control instructions. Further, the location information may beperiodically transmitted over the network to the web server on thenetwork so that the user of the center pivot irrigation system canaccess the periodically updated location information.

In one implementation of the method of the invention, a site on anetwork is provided for the purpose of monitoring and controlling thecenter pivot irrigation system, and the site is accessible over thenetwork by the user for at least these purposes. As previously noted, inat least some implementations the network is the Internet and the siteon the network is a website. A web page may be provided on the websitewith information pertaining to the center pivot irrigation system 10 ofinterest to the user, and the website may include other web pagesdirected to other center pivot irrigation systems and accessible to thisor other users of the system 10. The information may include, forexample, information about the current position of the rotatable arm andinformation about any control instructions currently loaded on thesystem and being executed by the system.

In some implementations, the website includes a plurality of maps and/orimages for facilitating initial setup of the invention on the user'ssystem, including the user's web page for the center pivot irrigationsystem. The user may be provided with a choice of utilizing aphotographic image of the area being irrigated by the subject centerpivot irrigation system, or a cartographic map of the area beingirrigated (for example, a political map or a topographic map).Optionally, a combination of these formats may be provided to the user.It should be recognized that other types of two dimensional andthree-dimensional representations of the area being irrigated may alsobe utilized. For the purposes of this description, the representation ofthe area being irrigated, whether a map or an image or other type ofrepresentation, will be referred to as a map/image. At least one of theplurality of map/images on the site may include one or more visualrepresentations of center pivot irrigation systems that may becontrolled, or are controllable, through the site.

An initial step of the initial set up process of the system 10 includesinstalling the elements of the system 10 on the center pivot irrigationsystem 1, such as is depicted in FIG. 4 of the drawings. The tower unit12 may be mounted on the tower of the tower 5 of the irrigation system1, and, depending upon the embodiment of the system 10 beingimplemented, the remote unit 14 may be installed on or by the irrigationsystem 10, and the remote unit 14 may be interfaced with the controlpanel 9 of the irrigation system to permit control by the remote unit 14of the control panel. At this point, the user may determine the locationof the center of rotation of the rotatable arm 3, which is typically thelocation of the center pivot 2, of the irrigation system 1 by anysuitable manner. The user may further determine the distance between thecenter of rotation, or center pivot, and the location of the tower unit12 on one of the towers 5 of the irrigation system 10.

Initially, a set up process may be initiated by the user to set up orinitiate the monitoring and/or controlling of the center pivotirrigation system, such as is depicted in FIG. 5 of the drawings. Theuser may be provided with access to the website on or through thenetwork for the purpose of providing initial information to permit apage or other record to be created for the particular center pivotirrigation system of the user to be controlled, to permit the centerpivot irrigation system to monitored and controlled via the website.

An initial step of the initial set up process for the website may allowthe user to indicate the location of the center pivot irrigation system1 to be controlled. This process may begin with the user's indication ofa location of the center pivot tower of the center pivot irrigationsystem, and the receipt by the website of the location. In someimplementations, the location is designated by the user in terms ofcoordinates, such as the latitude and the longitude, for the location ofthe center pivot tower. In other implementations, the user may simplyindicate a location in general terms, such as a general area (forexample, street address), and the site presents a map/image of the areaindicated if such a map/image is available. The user may then indicatethe location of the center pivot tower with greater precision throughthe interface, such as by using a cursor pointer on the interface.Generally, the provision of the coordinates of the center pivot tower ispreferred as typically being more accurate. Such coordinates may bedetermined in a number of different ways, but the user of a GPS devicemay be the most convenient.

Once the location of the center pivot 2 has been determined, a distanceor length of the rotatable arm 3 between the center pivot 2 of theirrigation system 1 and the position of the tower unit 12 on the arm 3may be provided by the user to the system 10. In most implementations ofthe invention, the tower unit 12 with the GPS signal receiver 16 ispositioned at the endmost tower of the rotatable arm, and thus thelength of the rotatable arm may be equal to the distance between thecenter pivot 2 and the endmost tower 7. This configuration is likely toproduce the most accurate locating of the system 1 using the GPS signalreceiver 16. As will be appreciated from the following, greater accuracyof monitoring and control is possible as the distance between the centerpivot tower and the tracking tower is increased.

The distance between the center pivot 2 and the endmost tower 7 may bedetermined through direct physical measurement in the field of thedistance. In a highly advantageous implementation of the invention,determining the distance involves positioning the tower unit 12 on theendmost (or other) tower 7 in the field. An initial location indicationis then received from the GPS receiver 16 of the remote unit 14 (throughthe cellular network 24). The location is then used to pull up themap/image of the area of the center pivot irrigation system 1, and thelocation of the center pivot 2 may be visually determined on themap/image by an operator using the map/image. Using the initial locationinformation received from the GPS receiver 16, and thevisually-determined location of the center pivot 2, the distance betweenthe remote unit 14 and the center pivot 2 may be determined remotely(after the remote unit 14 has been installed on the tower in the field)without having to physically and directly measure the distance betweenthe center pivot 2 and the tower.

The user may also provide to the website, and the system may receivefrom the user, other information about the center pivot irrigationsystem, such as whether the irrigation system has an end gun mounted onthe endmost tower of the rotatable arm, and what is the length of awater stream from the end gun.

If the user has additional center pivot irrigation systems 1 that are tobe controlled through the system 10, the user may repeat one or more ofthe steps described above for each of the irrigation systems. The systemmay provide monitoring and control aspects for a plurality of theirrigation systems.

In one significant aspect of the invention, such as is depicted in FIG.6 of the drawings, the initial set up process of the system 10 mayfurther include the generation of a set or range of coordinates thatcorrespond to the path of locations over which the GPS signal receiver16 of the tower unit 12 is estimated or expected to move along as therotatable arm rotates with respect to the center pivot. Using thecoordinates of the center pivot 2 provided by the user, and the lengthof the rotatable arm from the center pivot to the tower unit 12, an arcor circle of coordinates may be calculated for the path over which thetower unit is expected to travel throughout the movement of therotatable arm about the center pivot. This arcuate or circular path isgenerally centered on the center pivot 2 of the irrigation system 1, andincludes a line of coordinates located along the circumference of thearcuate or circular path, but does not include the interior locations ofthe arc or circle, such as the locations between the circumference andthe center pivot 2. Thus, the set of coordinates does not include thecoordinate of the center pivot 2, as the tower unit (and the GPSreceiver 16) will be maintained at a distance substantially equal to thelength from the center pivot 2 and will not move through the location ofthe center pivot 2. The coordinates of the path may be stored on thesystem for user retrieval when the user indicates the locations on themap/image that various control actions are to take place. Once the pathof the tower unit 12 has been calculated, the coordinates of the centerpivot is no longer used, and it is possible that the coordinate of thecenter pivot may be deleted after the calculation of the path. Thecoordinate of the center pivot 2 would not be needed again, unless forsome reason the path would need to be recalculated, such as, forexample, a change in the length from the center pivot to the tower unitand the GPS receiver.

It should be noted at this point that the coordinates of the path neednot be, and preferably are not, limited to just the coordinates of theprecise line of coordinates along the circumference of the arc or circleabout the center pivot at the precise distance of the tower unit fromthe center of rotation. The coordinates of the path may be expanded toinclude coordinates at a slightly shorter and slightly longer radiusdistance from the center pivot to create a band or strip of coordinatesalong the path that extends laterally from the circumferential line.This aspect of the invention can help to account for relatively smallvariations that may occur in the GPS coordinate readings made by the GPSsignal receiver as it is moving along the path, as well as variations inland topography that can also cause variation in the GPS readings by theGPS receiver.

Once the coordinates of the path of the tower unit have been determined,the sweep 30 of the rotatable arm may be visually represented ordepicted on the map/image 32 on the web page for the subject centerpivot irrigation system (see FIG. 7). The sweep 30 of the rotatable armmay be represented on the map/image by a different and preferablycontrasting color that overlies the portion of the map/image thatcorresponds to the circle (or portions thereof) over which the rotatablearm moves. The representation of the sweep 30 may be partiallytransparent or translucent so that some of the underlying detail of themap/image shows through the representation of the sweep. Thisvisualization of the sweep of the rotatable arm 3 can facilitate theuser's entry of control information for programming the system tocontrol the irrigation system, such as, for example, by the user movingthe cursor of the interface across the map/image 32 on the web page andclicking on the desired location of the rotatable arm 3 when the desiredaction is to take place. Further, a partial band 34 may be depicted onthe map/image 32 that indicates the operation (“on” state) of the endgun 8 along the perimeter of the sweep 30.

In another aspect of the method of the invention, a programming processof the system 10 may be implemented that includes an initial schedulingprocedure that is conducted on the web page and an instruction downloadprocedure that occurs after the initial scheduling procedure has beencompleted. The initial scheduling procedure may include the userinitiating an action record for the system, which corresponds to anaction or operation that the user wants the irrigation system to take ata particular location of the tracking tower. The number of actionrecords may be limited for each particular center pivot irrigationsystem to be monitored and controlled.

Upon the invocation of an action record, the user indicates the aspectof the center pivot irrigation system that is to be controlled. Forexample, many center pivot irrigation systems are provided with an endgun, and are also provided with the capability to turn the end gun onand off based upon the position of the rotatable arm. Further, thecenter pivot irrigation system often has the capability to start andstop the movement of the rotatable arm, change the direction of movementof the rotatable arm, turn a water pump on and off, adjust the rate atwhich the water is applied to the field, provide delays in the movementof the rotatable arm for a set period, as well as turn on and offvarious auxiliary devices and controls. To create or change the actionrecord, the user may indicate what type of action is to be taken, andthe action may be inputted by the user or may be selected from a list ofoptional actions on the web page. The user may indicate a position ofthe rotatable arm at which the selected action is to occur. Preferably,this indication is made by the user moving the cursor on the map/imageto the position of the rotatable arm at which the indicated action is tooccur, and clicking on that location. The system reads the position ofthe cursor at the point that the mouse or other pointing device isclicked, and records that position of the tracking tower in the actionrecord.

Upon the completion of the information in the action record, thedepiction of the center pivot irrigation system may be updated toreflect the inclusion of the action record in the operation program forthe irrigation system. For example, the operation of the end gun may bedepicted in the map/image by an arcuate band that extends along theportion of the sweep of the rotatable arm that corresponds to the endgun being turned on, and the band may terminate at the location on thesweep that the gun is turned off. The user is thus provided with avisual indication on the map/image of the portions of the sweep at whichthe end gun is operating, and may provide a depiction of the area of thefield that is being watered by the operation of the end gun. As anotherexample, different modes of operation of the rotatable arm may bedepicted on the sweep on the map/image by areas of different colors, sothat, for example, an area over which the rotatable arm moves forwardlyis depicted in one color, an area over which the rotatable arm moves ina reverse direction may be depicted in another color, and otheroperations may be shown in other different colors.

When the user indicates that the operation of the center pivotirrigation system that is represented in the action records is to beimplemented, the instruction download procedure is initiated. The system10 assembles the action records and coordinates information together fordownload to the remote unit 14 through the various communicationnetworks.

With respect to the above description then, it is to be realized thatthe optimum dimensional relationships for the parts of the invention, toinclude variations in size, materials, shape, form, function and mannerof operation, assembly and use, are deemed readily apparent and obviousto one skilled in the art in light of the foregoing disclosure, and allequivalent relationships to those illustrated in the drawings anddescribed in the specification are intended to be encompassed by thepresent invention.

Therefore, the foregoing is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described, and accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of theinvention.

1. A method for determining a position of a rotatable arm of a centerpivot irrigation system, comprising: providing a pivot arm positionsensing system including a tower unit positionable on the rotatable armof the irrigation system at a position spaced from a center of rotationof the rotatable arm, the tower unit including a Global PositioningSatellite (GPS) receiver; receiving, from a user of the irrigationsystem over a communication network, a schedule for operating theirrigation system as the rotatable arm rotates, the schedule includingat least two instructions for taking an action by the irrigation system,each instruction including an action to be taken by the irrigationsystem and corresponding location coordinates at which the action is tobe taken, downloading the schedule of instructions over a wirelesscommunication network to storage on the position sensing system;determining location coordinates of the tower unit as the tower unitmoves along a path of the tower unit as the rotatable arm pivots aboutthe center of rotation using the GPS receiver on the tower unit; andinitiating an action by the irrigation system by the position sensingsystem when the location coordinates of the tower unit correspond to thelocation coordinates in one of the instructions stored on the positionsensing system.
 2. The method of claim 1 additionally comprisingcomparing the current location coordinates of the tower unit to thecorresponding location coordinates associated with of one of theinstructions.
 3. The method of claim 2 wherein the step of comparingoccurs at the remote unit.
 4. The method of claim 2 wherein, if asubstantial match of current location coordinates with one of thecorresponding location coordinates associated with one of theinstructions is detected, the action corresponding to the instruction isinitiated by the remote unit through controls of the center pivotirrigation system.
 5. The method of claim 1 wherein the downloading ofthe schedule of instructions is performed over a cellular telephonecommunication network.
 6. The method of claim 1 additionally comprisinginterfacing a remote unit of the position sensing system to controls ofthe irrigation system, and wherein the schedule of instructions aredownloaded over the wireless communication network to the remote unitand through the remote unit to the controls of the irrigation system tocause an action by the irrigation system.
 7. The method of claim 1additionally comprising transmitting the location coordinates of thetower unit by the position sensing system over the wirelesscommunication network to a server in a location remote from theirrigation system.
 8. The method of claim 7 wherein the server isinterfaced to a second network through which data regarding the locationcoordinates is accessible by a user.
 9. The method of claim 7additionally comprising displaying, on a site generated by the serverand accessible by a user over a communication network, a depiction ofthe corresponding position of the rotatable arm in a representation ofan agricultural field corresponding to the transmitted locationcoordinates.
 10. The method of claim 9 wherein the depiction includes avisual indication indicating a position of the rotatable arm at which anaction is to be taken by the irrigation system.
 11. The method of claim7 additionally comprising storing on the server the schedule including aplurality of the instructions.
 12. The method of claim 1 additionallycomprising providing a site on a network for monitoring a position ofthe rotatable arm and controlling actions of the center pivot irrigationsystem based upon location coordinates transmitted to a server over thecommunication network.
 13. The method of claim 12 additionallycomprising determining on the server an arc of location coordinatescorresponding to locations of the tower unit as the rotatable armrotates about the center of rotation, and visually depicting the arc oflocation coordinates on the site.
 14. A system for determining aposition of a rotatable arm of a center pivot irrigation system, therotatable arm of the irrigation system being rotatable about a centerpivot, the system comprising: a tower unit for positioning on therotatable arm at a distance from the center pivot of the irrigationsystem, the tower unit comprising: a Global Positioning Satellite (GPS)receiver configured to determine location coordinates of the tower unit;a first transmitter for communicating the location coordinates; and aremote unit for positioning proximate to the tower unit for receivinglocation coordinates from the tower unit, the remote unit comprising: afirst receiver for receiving the location coordinates transmitted by thefirst transmitter of the tower unit; a second transmitter configured totransmit the location coordinates of the tower unit to a location remotefrom the irrigation system over a communication network; storageconfigured to store a schedule of instructions downloaded to the remoteunit; and a comparator configured to compare the location coordinates ofthe tower unit to at least one location of one of the instructionsstored in the storage.
 15. The system of claim 14 wherein the firsttransmitter comprises a radio transmitter configured to communicate withthe second transmitter of the remote unit.
 16. The system of claim 14wherein the second transmitter comprises a cellular telephone and thecommunication network comprises a cellular telephone network.
 17. Thesystem of claim 14 wherein the remote unit is interfaced to controls ofthe center pivot irrigation system and the remote units is configured tocause the center pivot irrigation system through the controls to take anaction of one of the instructions when the location coordinates of thetower unit substantially match location coordinates of one of theinstructions.
 18. The system of claim 14 wherein the tower unit ispositionable at an end tower of the irrigation system.